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xvs 125 you can get a bit more poke


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Wow, that's a real huge jet range for one engine, I just thought that 110 would be too much because it's already the stock size for the xvs 250...

Well, appearently it is not too much.The 110# jet arrived and I went on a test ride. In the bottom to mid rpm range the engine seems to have slightly more torque, but I still can only squeeze it to just under 60mph and drop back at least 10mph on the flat when shifting to 5th gear.
Top speed beyond 60 and permanently cruising at 60 is just not possible, it is a mystery to me how other people in this thread achieve those results with the listed mods, it just doesn't seem to work right for me...
If anyone has some ideas, please let me know, I want to properly benefit from those mods,too...


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I could get 70mph flat out on a flat stretch, cruise at 60mph, only having to drop down the gears for steep hills. I tried one tooth up and one tooth down on the front, but lost out using both at either end of performance, so kept the stock gears gears. The rest of the bike was also stock. I also only used Super unleaded. My own view is that people pissed about with them for little gain, given that the engine is only a 125, pulling a fair weight. They are lovely little bikes

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Hi all

With regarding xvs 125 give a little more poke

When I was 16 on my first moped that would also do 70- 75 on a good day

My 125 would do about 110ish

You will be able to find out whether it's restricted by final  drive sprockets carb inlet size main jets needle height Exhaust But you must do everything not just one as doing just 1 will make the bike run lean then seize or blow up...

If you have the money then get a big bore kit


On 6/15/2010 at 10:16 PM, islaylag said:

help, trying to get my front drive sprocket of my xvs 125,had torque wrench on and lifting bike off ground nut still refuses to move,i have bent the three locking tabs back, is it a l/h or r/h thread

lol maybe you should pop down your local tire garage and ask them to use an air wrench or a 6ft bar on the end and lightly tap the socket with a hammer to crack the seal

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  • 2 weeks later...

Sorry, didnt have much time to work on the bike and reply here, but there's some news:

To make sure everything is Ok with my bike I reverted it completely to stock again (exhaust, filter, jet and sprocket) and it still wouldnt go any faster than about 58mph and MUCH less on slight uphill but oddly not much more on downhill.
Given the fact that its a real heavy 125cc cruiser, I usually wouldnt bother, but many DragStars seem to run better.

I am now going to take it apart to access the carb and adjust the valves (appearently never done before I bought it and has about 15.000km on the clock).

I also found out that it was restricted to 80km/h before I bought it, the pre owner said this was achieved with metal Rings in the headers, but they were already removed when I bought the bike.
However, I wonder if there's any other restrictions because that's how the bike feels...

For the valve adjustment I read that the intake should be 0.08mm-0.12mm and exhaust 0.10mm-0.14mm, can anyone confirm this?
And does someone have torque specs for the little lock nuts on the adjuster? 

Thanks :)

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  • 3 weeks later...

The wee pipes in end of exhaust is just a plate 2 restrict gas getting out so wat i did was i burst the wee pipes out and cored a bigger hole in the exhaust with a cone corer and also drilled out baffles inside exhaust i can now get 2 80mph flat out everything is still stock and gives u a much better sound 

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  • 4 weeks later...


By now i have tried every possible combination of valve setting (within the tolerances of course), air filter, sprocket, exhaust (stock/Highway Hawk straight pipes/BSM vline and Open headers), and every jet from 90 to 110.

No matter what I do I cant sqeeze more than 50-55 average from the bike, downhill and extreme rpm might get me up to 58, but thats rare.

Top speeds of 65 and above are definitely not possible with that bike in it's current condition and I just cant figure out what I am overlooking...

If they all would be that slow, i wouldn't even bother, but the fact that I know that it's not running Right is driving me nuts.

I think the problem is that there is still something from that stupid 80km/h (about 50mph) restriction left, but I cant figure it out...

And also, how many notches should the stock main needle in the carb have?

Thanks for helping me?

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